Measurement of transdermal alcohol is potentially a very unobtrusive, inexpensive and accurate way of continuously studying the alcohol consumption behavior of subjects in research and field settings as well as for monitoring special populations. Several innovative technological advances in ectrochemical sensing, materials science and engineering are proposed that will result in a novel transdermal alcohol sensing system to measure blood alcohol concentration. The proposed sensor will go beyond the current Giner Inc. patented technology and constitute new, innovative, and potentially patentable technology. The new sensor will require virtually no maintenance, have a very rapid response time, be more comfortable to wear, allow transfer of data from the home, and be less expensive to manufacture. In summary, the proposed product is a robust, comfortable sensor worn on the wrist that detects blood alcohol transdermally (10-200 mg/dl) and has low maintenance requirements, wireless communication and is economical to manufacture. The Specific Aims of the Phase I program are to: 1) design and evaluate a low maintenance system to maintain sensor hydration. 2) investigate sensor configurations which are amenable to utomated/semi-automated manufacturing techniques 3) introduce low-power, optical, wireless communication and 4) demonstrate the performance of the Phase I prototype in a clinical setting. Commercial Potential: There a number of markets for a continuous, noninvasive alcohol monitor: 1) Research and clinical treatment programs. 2) Emergency room setting for individuals that are unconscious, incapacitated, or unable to exhale forcibly. 3) Monitoring of professionals with or without known alcohol problems in sensitive industries (aviation, nuclear). 4) Monitoring drivers with prior DWI/DUI convictions. 5) Criminal justice system, where the court needs to monitor alcohol abstinence of convicted criminals on parole, probation or house arrest.